Seed, mature reproductive body of angiosperms and gymnosperms (seed-bearing plants). It also represents a resting stage that enables plants to survive through unfavorable conditions. Seeds develop from the fertilized ovule. Each seed is covered with a tough coat called a testa, and contains a young plant or embryo. In most seeds three main regions of embryo can be recognized: a radicle, which gives rise to the root; a plumule, which forms the shoot; and one or two seed leaves, or cotyledons, which may or may not be taken above ground during germination. Plants that produce one seed leaf are called monocotyledons and those that produce two, dicotyledons. The seed also contains enough stored food to support embryo growth during and after germination. It is this stored food that is of value to animals. Flowering plants produce their seeds inside a fruit, but the seeds of conifers lie naked on the scales of the cone. Distribution of seeds is usually by wind, animals, or water, and the form of seeds is often adapted to a specific means of dispersal.
See also: Reproduction.